These days, endoscopes are used for a multiplicity of applications in medicine and technology. Endoscopes typically comprise a rigid or flexible elongate shaft, which is suitable for insertion into a cavity, and in the distal (i.e. observer-distant) end region of which an objective is arranged for generating an image of an object field in the cavity. In order to record and transmit the endoscopic image from the distal end of the endoscope to the proximal (observer-near) end, provision can be made for an electronic image recorder, e.g. a CCD chip, in the region of the distal end of the shaft and for electric lines within the shaft. The image recorded by the electronic image recorder can be evaluated by an evaluation and display apparatus connectable to the proximal end of the endoscope, depicted on a screen for an observer and/or stored, e.g. for documentation purposes. Since, in general, the observed cavity does not have sufficient amounts of light, a light guidance system is furthermore provided within the shaft in order to transport sufficient amounts of light to the distal end of the endoscope, where it is used for illuminating the cavity.
If an endoscope comprising an objective and an electronic image recorder assigned to said objective in the distal end region of said endoscope is rotated about the longitudinal axis of the shaft, the recorded image depicted on the screen is also rotated in the process. This makes it difficult or impossible for an observer, who may be e.g. the surgeon performing a surgical operation, to orient himself or herself within the cavity. This applies, in particular, if the endoscope comprises a stereo optical system for generating a stereoscopic image, since the stereo basis is also rotated in this case.
JP 10192233 A has disclosed a stereoscopic electronic endoscope comprising an oblique view optical system, wherein provision is made for a motor-driven adjustment of a rotation element, which supports an optical system comprising two objective lens systems which are spaced apart transversely in relation to the optical axis, and two CCD image recorders assigned thereto. The signal cables of the CCD image recorders are routed in a flexible tube in an axial bore of the rotation element. U.S. Pat. No. 5,689,365 has disclosed a stereoscopic endoscope, which comprises a front optical system with a single optical axis and a rear optical system with a plurality of optical axes. Together with two photoelectric image recorders, the rear optical system can be rotated about an axis parallel to the shaft of the endoscope relative to the front optical system. The signal line of the image recorders is routed and twisted in the extension of the axis of rotation of the stereo optical system. The above-described arrangements are not ideal in respect of the durability of the cables.
DE 10 2011 054 031 A1 has disclosed a device for observing and illuminating an object field on a patient from a location away from the body of the patient, comprising an optical system for observing the object field and an illumination apparatus for illuminating the object field. The device furthermore comprises a shaft, at the distal end of which a head part is arranged, which head part is widened compared to the shaft and in which at least one emitting illumination unit for homogeneous illumination of the object field is arranged. Feed lines for the at least one illumination unit extend through the shaft. Furthermore, the elongate shaft can hold an image forwarding apparatus, which forwards the image of the operation field to a proximal end of the shaft. Such a device is also referred to as “exoscope”. In particular, such an exoscope enables the illumination and observation of an operation field during a surgical operation from a working distance of e.g. 25 to 75 cm such that the work space of the surgeon remains practically unrestricted by the exoscope. To this end, the exoscope can be affixed on a holder in a suitable position and with a suitable orientation. The aforementioned problem that the image recorded by an electronic image recorder is rotated on the screen, on which it is displayed for an observer, when the exoscope is rotated also arises in the case of an exoscope.